Suspension system for crawler tractor

ABSTRACT

A suspension system for resiliently supporting a crawler tractor that includes a plurality of wheel strut assemblies located at each side of the tractor. Each of the wheel strut assemblies have a housing that supports a wheel carrier for oscillatory movement about a longitudinal axis that extends transversely to the tractor and also for vertical movement.

United States Patent 1 Mazzarins 51 Feb. 27, 1973 SUSPENSION SYSTEM FORCRAWLER TRACTOR [75] Inventor: Janis Mazzarins, Macedonia, Ohio [73]Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: July 2, 1971 21 Appl. No.: 159,195

[52] US. Cl. ..180/9.2 R, 305/27 [51] Int. Cl. ..B62d 55/16 [58] Fieldof Search 180/92, 9.54; 305/27 [56] References Cited UNITED STATESPATENTS 2,405,733 8/1946 Boldt ..180/9.2 R 1,515,167 11/1924 Penn..305/27 1,901,269 3/1933 Snow ..305/27 X 2,860,715 11/1958 Bouffort...'.305/27 X FOREIGN PATENTS OR APPLICATIONS 574,613 5/1933 Germany..l80/9.2

Primary Examiner-Richard J. Johnson Attorney.l. L. Carpenter et al.

[57] ABSTRACT A suspension system for resiliently supporting a crawlertractor that includes a plurality of wheel strut assemblies located ateach side of the tractor. Each of the wheel strut assemblies have ahousing that supports a wheel carrier for oscillatory movement about alongitudinal axis that extends transversely to the tractor and also forvertical movement.

4 Claims, 4 Drawing Figures PATENTED FEBZ 7 I975 I N VEN TO R Janismazzerzks ATTORNEY SUSPENSION SYSTEM FOR CRAWLER TRACTOR Most crawlertractors that are manufactured at the present time include a main framewhich is adapted to be supported on a pair of laterally spaced andlongitudinally extending roller frames. Each roller frame rotatablycarries a plurality of track rollers which serve to support the weightof the tractor and provide track alignment. The rear end of each rollerframe is supported in a manner so as to permit it to pivot relative tothe other roller frame as the vehicle negotiates irregular terrainthereby maintaining constant drive irrespective of ground conditions.

Over the years, various improvements have been made to the design of thetrack rollers, however, the reoccurring problem of frequent replacementand repair of the rollers in order to maintain the tractor in properoperating condition has not been solved. As should be apparent, suchreplacement and servicing of the track rollers is a large expense duringthe life of a crawler tractor and, accordingly, there have beenproposals to eliminate the usual track rollers and substitute thereforlarge diameter wheels, the maintenance cost of which would besubstantially less than that of the presently utilized track rollers.

The present invention is directed to a crawler tractor having largediameter wheels and more particularly to a suspension system forresiliently supporting the large diameter wheels so as to permit thevehicle to maintain track contact with the ground under most conditionsof operation. More specifically, the present invention contemplates asuspension system for a crawler tractor that includes a plurality ofwheel strut assemblies located at each side of the tractor along an axisparallel to the longitudinal axis of the tractor. Each of the wheelstrut assemblies has a housing rigidly attached to the tractor andincludes a wheel carrier supported by the housing in a manner so as topermit the wheel carrier to move vertically relative to the tractor and,in addition, pivot about a horizontal axis extending transversely to theaforesaid longitudinal axis. In the preferred form, the wheel carrier isL-shaped, with one leg serving as a support for the track wheel. Theother leg of the wheel carrier extends into the housing and is supportedby a bearing that provides for the vertical movement as well as thepivotal movement of the track wheel. Spring means attached to thetractor cooperate with a part of the wheel carrier for cushioningmovement of the latter.

The objects of the present invention are to provide a suspension systemfor a crawler tractor which includes a plurality of individual wheelstrut assemblies supported so as to move in a vertical direction towardand away from the tractor and also oscillate about a horizontal axisextending transversely to the longitudinal axis of the tractor as thelatter traverses irregular terrain; to provide a wheel strut assemblyfor resiliently supporting a track wheel of a crawler tractor that ismovable in a vertical plane and, in addition, can oscillate about atransverse axis; to provide a suspension system for a crawler tractorhaving large diameter wheels which includes a plurality of independenttrack wheel strut assemblies, each of which resiliently supports thelarge diameter track wheel for vertical movement relative to the tractorand also oscillatory movement about a transverse axis; and to provide asuspension system for a crawler tractor having a plurality ofindependent resiliently supported wheel-carrying struts located on eachside of the tractor forwardly of the drive sprocket and interconnectedby a link to a track adjusting device which serves to tension theendless track.

Other objects and advantages of the present invention will be moreapparent from the following detailed description when taken with thedrawing in which:

FIG. 1 is a side elevational view showing a crawler tractorincorporating a suspension system made in accordance with the invention;

FIG. 2 is an enlarged sectional view taken on line 2- 2 of FIG. 1showing one of the wheel strut assemblies incorporated with thesuspension system of FIG. 1;

FIG. 3 is an enlarged sectional view taken on line 3 3 ofFIG. l; and

FIG. 4 is a view taken on line 4-4 of FIG. 2.

Referring to the drawing and particularly FIG. 1, a crawler tractor 10is shown comprising the usual main frame 12, the front end of which hasan engine compartment 14 having a conventional internal combustionengine (not shown) that provides drive through a suitable transmissionto a pair of laterally spaced drive sprockets, one of which only isshown and identified by the reference numeral 16. Located forwardly ofeach drive sprocket 16 on each side of frame 12 are a plurality of largediameter track wheels identified by the numerals 18, 20, 22, and 24. Itwill be noted that trackwheels 18 and 22 are each integrally formed witha peripheral radially extended band 26 adapted to be received by asuitable groove formed in the central inner portion of an endless track28. On the other hand, the track wheels 20 and 24 are each formed with apair of laterally spaced integral discs 30 and 32 which straddle thetrack wheels 18 and 22 and engage the inner portions of the endlesstrack 28 so as to provide positive alignment thereof during drivingoperation of the crawler tractor 10.

Each of the track wheels 18, 20, 22, and 24 is supported by a wheelstrut assembly 34 which provides for movement of the associated trackwheel in a vertical direction as well as pivotal movement about ahorizontal axis extending transversely to the longitudinal axis of thetractor. Each of the wheel strut assemblies 34 is identical inconstruction and as seen in FIGS. 2 through 4, is mounted in a housingwhich is formed by a pair of vertical plate members 36 and 38 which arerigidly secured to the main frame 12 of the tractor 10. Located betweenthe plate members 36 and 38 is a bearing member 40 formed with a pair ofaxially aligned pivot pins 42 and 44 which are respectively receivedwithin bores 46 and 48 formed in the plate members. A generally L-shapedwheel carrier 50 has a leg 52 slidably received within the bearingmember 40, while the other leg 54 extends laterally outwardly andsupports the associated track wheel thereon for rotation about atransverse horizontal axis. It will be noted that the leg 52 isrectangular in cross section and is accommodated by a similarly formedopening within the bearing member 40 so as to permit the wheel carrier50 to have movement relative to the frame 12 in a vertical direction.This movement is additive to the aforementioned oscillatory movementprovided by the pivot pins 42 and 44 supported in the plate members 36and 38. Also, the upper end of the leg 52 terminates with an offset arm58 which is bonded to the underside of an elastomeric member 60. Theupper end of the elastomeric member is secured to the main frame 12 ofthe tractor through an arcuate plate 62. Thus, when the wheel carrier 50moves vertically upward, such movement is cushioned by the elastomericmember 60.

A track tensioner or adjusting device 64 is connected with each wheelstrut assembly 34 and comprises relatively movable cylinder and pistonmembers 66 and 68. As seen in FIG. 1, the cylinder member 66 isconnected by a pivotal connection 70 to the main frame 12 of the tractor10, while the piston member 68 is pivotally connected through anelongated link 72 to the bearing member 40 of each of the wheel strutassemblies. In this regard, it will be noted that each bearing member 40includes an integrally formed upwardly extending arm 74 with a pivotalconnection 76 for joining the arm 74 to the link 72.

From the above description, it should be apparent that the suspensionsystem made according to the invention is such that when the crawlertractor 10 is operating on flat ground, each of the wheel strutassemblies 34 is located in the positions shown in FIG. 1. However, whenthe tractor is driven over irregular ground having valleys or ridges,each of the track wheels 18, 20, 22, and 24 will move either upwardly ordownwardly relative to the main frame in accordance with groundconditions so as to maintain track engagement with the ground. Theaforementioned upward movement of any of the track wheels will becushioned by the elastomeric member 60 so as to reduce jarring of thetractor operator and thereby provide a smoother ride. As a result, thetractor can operate at increased speeds.

The track tensioner 64 can be of the type shown in my U.S. Pat. No.2,837,380, which is assigned to the assignee of this invention, andconsists of a nitrogen gas recoil cylinder and hydraulic jack adjuster.This amounts to a two-part construction so that on the reaction side ofthe piston, nitrogen absorbs all shocks and on the return side,semi-fluid grease stops and retains the position of the piston and,accordingly, maintains track tension.

Various changes and modifications can be made in this constructionwithout departing from the spirit of the invention. Such changes andmodifications are contemplated by the inventor and he does not wish tobe limited except by the scope of the appended claims.

I claim:

1. A wheel strut assembly for resiliently supporting the track wheel ofa crawler tractor comprising, a housing having an upper end and a lowerend, said housing adapted to be rigidly secured to the crawler tractorand having a bearing member supported for pivotal movement about ahorizontal axis located intermediate said upper and lower ends of saidhousing and extending transversely to the longitudinal axis of thetractor, a wheel carrier having one end thereof serving as an axle forrotatably supporting the track wheel, the other end of the wheel carrierbeing generally rectangular in cross section and supported by saidbearing member for vertical movement relative thereto and for pivotalmovement with said bearing member about said horizontal axis, and springmeans adapted to be attached to said crawler tractor and cooperatingwith a part of the wheel carrier for cushioning movement of the wheelcarrier as the latter moves relative to the bearing member.

2. A wheel strut assembly for resiliently supporting the track wheel ofa crawler tractor comprising, a housing having an upper end and a lowerend, said housing adapted to be rigidly secured to the side of thecrawler tractor and having a bearing member supported for pivotalmovement about a horizontal axis located intermediate said upper andlower ends of the housing and extending transversely to the longitudinalaxis of the tractor, an L-shaped wheel carrier having one leg thereofserving as an axle for rotatably supporting the track wheel, the otherleg of the wheel carrier being generally rectangular in cross sectionand supported by said bearing member for vertical movement relativethereto along the longitudinal axis thereof and for pivotal movementwith said bearing member about said horizontal axis, and spring meansadapted to be attached to said crawler tractor and cooperating with saidother leg of the wheel carrier for cushioning movement of the wheelcarrier as the latter moves relative to the bearing member.

3. A suspension system for a crawler tractor including a plurality ofwheel strut assemblies located at each side of said tractor along anaxis parallel to the longitudinal axis of the tractor, each of saidwheel strut assemblies having a housing rigidly attached to the tractor,a wheel carrier supported by said housing for oscillatory movement abouta first horizontal axis extending transversely to said longitudinal axisand for movement along a vertical axis, said wheel carrier having theform of a strut with one end thereof serving to support a track wheelfor rotation about a second horizontal axis located below said firsthorizontal axis, a bearing member mounted in said housing for pivotalmovement about said first horizontal axis and supporting the other endof the wheel carrier for relative movement along said vertical axis,spring means carried by the tractor for cushioning movement of saidwheel carrier along said vertical axis, a drive sprocket supported oneach side of the tractor in longitudinal alignment with the track wheelslocated on the same side of the tractor, an endless track entrainedabout each drive sprocket and the associated track wheels, and a trackadjusting device mounted on the tractor and pivotally connected to thebearing member of each of the wheel strut assemblies for tensioning saidendless track.

4. A suspension system for a crawler tractor including a plurality ofwheel strut assemblies located at each side of said tractor along anaxis parallel to the longitudinal axis of the tractor, each of saidwheel strut assemblies having a housing rigidly attached to the tractor,a wheel carrier supported by said housing for oscillatory movement abouta first horizontal axis extending transversely to said longitudinal axisand for vertical movement, said wheel carrier being L-shaped with oneleg serving to support a track wheel for rotation about a secondhorizontal axis located below said first horizon tal axis, a bearingmember mounted in said housing for pivotal movement about said firsthorizontal axis and supporting the other leg of the wheel carrier forvertical movement, spring means carried by the tractor for cushioningvertical movement of said wheel carrier, a drive sprocket supported oneach side of the tractor in longitudinal alignment with the track wheelslocated on the same side of the tractor, an endless track entrainedabout each drive sprocket and the associated track wheels, a linkmember, and a track adjusting device mounted on the tractor andpivotally connected to the 5 bearing member of each of the wheel strutassemblies by said link member for tensioning the endless track.

1. A wheel strut assembly for resiliently supporting the track wheel ofa crawler tractor comprising, a housing having an upper end and a lowerend, said housing adapted to be rigidly secured to the crawler tractorand having a bearing member supported for pivotal movement about ahorizontal axis located intermediate said upper and lower ends of saidhousing and extending transversely to the longitudinal axis of thetractor, a wheel carrier having one end thereof serving as an axle forrotatably supporting the track wheel, the other end of the wheel carrierbeing generally rectangular in cross section and supported by saidbearing member for vertical movement relative thereto and for pivotalmovement with said bearing member about said horizontal axis, and springmeans adapted to be attached to said crawler tractor and cooperatingwith a part of the wheel carrier for cushioning movement of the wheelcarrier as the latter moves relative to the bearing member.
 2. A wheelstrut assembly for resiliently supporting the track wheel of a crawlertractor comprising, a housing having an upper end and a lower end, saidhousing adapted to be rigidly secured to the side of the crawler tractorand having a bearing member supported for pivotal movement about ahorizontal axis located intermediate said upper and lower ends of thehousing and extending transversely to the longitudinal axis of thetractor, an L-shaped wheel carrier having one leg thereof serving as anaxle for rotatably supporting the track wheel, the other leg of thewheel carrier being generally rectangular in cross section and supportedby said bearing member for vertical movement relative thereto along thelongitudinal axis thereof and for pivotal movement with said bearingmember about said horizontal axis, and spring means adapted to beattached to said crAwler tractor and cooperating with said other leg ofthe wheel carrier for cushioning movement of the wheel carrier as thelatter moves relative to the bearing member.
 3. A suspension system fora crawler tractor including a plurality of wheel strut assemblieslocated at each side of said tractor along an axis parallel to thelongitudinal axis of the tractor, each of said wheel strut assemblieshaving a housing rigidly attached to the tractor, a wheel carriersupported by said housing for oscillatory movement about a firsthorizontal axis extending transversely to said longitudinal axis and formovement along a vertical axis, said wheel carrier having the form of astrut with one end thereof serving to support a track wheel for rotationabout a second horizontal axis located below said first horizontal axis,a bearing member mounted in said housing for pivotal movement about saidfirst horizontal axis and supporting the other end of the wheel carrierfor relative movement along said vertical axis, spring means carried bythe tractor for cushioning movement of said wheel carrier along saidvertical axis, a drive sprocket supported on each side of the tractor inlongitudinal alignment with the track wheels located on the same side ofthe tractor, an endless track entrained about each drive sprocket andthe associated track wheels, and a track adjusting device mounted on thetractor and pivotally connected to the bearing member of each of thewheel strut assemblies for tensioning said endless track.
 4. Asuspension system for a crawler tractor including a plurality of wheelstrut assemblies located at each side of said tractor along an axisparallel to the longitudinal axis of the tractor, each of said wheelstrut assemblies having a housing rigidly attached to the tractor, awheel carrier supported by said housing for oscillatory movement about afirst horizontal axis extending transversely to said longitudinal axisand for vertical movement, said wheel carrier being L-shaped with oneleg serving to support a track wheel for rotation about a secondhorizontal axis located below said first horizontal axis, a bearingmember mounted in said housing for pivotal movement about said firsthorizontal axis and supporting the other leg of the wheel carrier forvertical movement, spring means carried by the tractor for cushioningvertical movement of said wheel carrier, a drive sprocket supported oneach side of the tractor in longitudinal alignment with the track wheelslocated on the same side of the tractor, an endless track entrainedabout each drive sprocket and the associated track wheels, a linkmember, and a track adjusting device mounted on the tractor andpivotally connected to the bearing member of each of the wheel strutassemblies by said link member for tensioning the endless track.